Loading system



Dec. 27, 1927.

W. FON DILLER LOADING SYSTEM mlazs I /m/enfo/f PVM/Mm fnd/Wer.' /d A@ dii Patented Dec. 27, 1927.

UNITED STATES PATENT OFFICE."

WIliIilAM.' FONDILLER, OF NEW YORK, N. Y., AESGNOR TO WESTERN ELECTRIC COM- PANY, IIiiOOIEtEORAIED, OF NEW' YORK, N. Y., A CORPORATION OF NEW YORK.

LOADING SYSTEM.

Application leil May il, 1923, Serial No. 6373474. Renewed (ictober 1924.

This invention relutes to loadingl systems und niore particuliirly relates to :in arrange nient for loading signaling' lines such as telepl'ione or telegraph cables.

in object of this invention is to provide an ellicient loadingl systen'i ior signal condoctors such us underground or aerial toll cables7 particularly lor signaling currents in the ultra audio frequency range.

The :torno of this invention hereinafter described in detail is eiiiployed `.Vith particular :idmntzigeliifor loading toll cables ll'or the so-called carrier frequency range whereby cllicient transmission muy telic pluco along the ciible :tor ultru laudio frequencies.

Connnercial luinped loading oii the Pupin typeis, is is well known in lthe art the equivalent et ii lonv piiss Wave tilter which gives 'tree triinsinission for :ill :ifrequencies below u. delinite cut-oil frequency, fc, given by the equation,

Since lfor lumped loadingof the Pupin `type the distance between coils inust be decreased to secure an increase in the upper liiniting?l range to be transmitted, or other 'wise smaller inductiinces must be used with a resultingv high attenuation, such a large nuniber `oli loading coils is required to loud the cable lior curr-ier frequencies us coniu pared to the nuinber required tor speech l'requency transmission thzit the cost is iilinost prohibitive, even taking into account the eXtra signa-ling, channels obtained by the raising of the upper limiting' frequency. rlilie relatively large amount ol space required by loading coils is highly objection uble in inany cases, as in underground cables Where the loading coils ure placed in iniinholes andthe spiice available in limited und costly. On the other hand continuous loadin@- oi the conductors by :in individual Wrapping; of inugnctic material is also open to objection becziuse oli the high cost due 'to increased size of crible7 increased ductspace, shipping Weight, etc. rlhe overall size oit a czible is furthermore liniited by various econon'iiciil and nuiniiifiicturing conditions so that if euch quad must be continuously loaded the entra space required will reduce considerably thc nuuiber olf quads that may be placed in the standard size of cable. The lending arrangement proposed tor this invention ii coniproinisc between continuous und lumped li'iadingl whereby the objections to each oi these methods :ire inininiized to a substantial degrec.

lnstea-(il ol' liavingji4 each conductor olf the cable continuously loaded :dong its entire lengtln it is proposed to apply the coi'itiiiiu ous loudingl to only zilfrzictional part oli' the conductors iii each section of the czible, the continuously loaded conductors olE one section beingl so connected t-o non-loaded condoctors oil' the adjacent sections that the loaded sections are uniliornily distributed along each signaling path and are 'joined by the suine lengths oi: non-loaded conductors. For enziinplc, one-hull1 oit the totalnuinbcr of condilictors in one section oi' the crible iniiy bc continuously loaded, while the reniiiininibT heli are non-loaded. ln splicing cable u continuously loaded quod `would then be connected to ii no|i-.l,oiidcd quad iii the succeeding section und so on. .ik-n, obvious extension ol this would bc to loiid only one-third or one-:fourth olf the quads in each section .so that the loaded quod ci' one section would be connected to a non-loiided quod in the nent two or three sections, :is the cose inay be.

in euibodiinent ot this invention dis closed in the acconiipanyinil draii'iiie.

Referring in detail to the drawing, ii portion ol? ii telephone crible is disclosed, diiiid ed tor convenience, into three sections, designated A, B5 und C. Each oi these sections is shown to comprise only leur quiids, although in. connnerciiil practice :i telephone toll crible comprises a niucli larger number of quadsa und consequently oit conductors. In order to obtain satisfactory transmission through the cable, purtieularly lor carrier frequencies up to 30,00() cycles, 30,000 cycles, or incre, it :is proposed to apply continuous loading to one-luill of the quiids or conductors in euch section of the crible, the loiidcifl quads or conductors in one section being;` connected to noiidoadcd quads or ci'indui'rtors in the succeeding section, :ind so on, so that the continuously loiidilid sections olf' any transmission line through the cabi-e will ocn cur ut constant intervals. rlfhis will7 ol" course, resultin a compromise betii'ecn coutinuous loading; along,l the entire lengt-h of nwhat higher when` the loading is in accordeach conductor and lumped loading wherein loading coils are spaced at uniform distances along the transmission lines.

In section A of the cable, the pairs of conductors 5, 6, 7 and 8 are shown to be continuously loaded by a suitable wrapping of a proper magnetic material composed, foil example, of iron-nickel alloy, while the pairs 9, 10, 11 and l12 are nonnloaded. Similarly, pairs 13 to 16of section B and pairs 21 to 24 of section C are continuously loaded, while pairs 17 to 20 of section B and pairs 25 to 28 of section C are non-loaded. The loaded quads 5, 6 and 7, 8 of section A are connected to the non-loadedwquads 17, 18 and 19, 20 of section B and ,then to the loaded quads 21, 22, and 23, 24 of section C. Similarly, the non loaded quads 9, 10 and 11, 12 of section A are connected to the loaded quads 13, 14 and 15, 16 of sect-ion B and then to the non-loaded uads25, 26, and 27, 28 of section C, so that or any lone particular transmission line the Vloaded sections and thenon-loaded sections are alternated.

The material employed in obtaining the continuous loading is not a part of this invention, since any suitable material may be employed having the proper permeability and a sufficiently high specific resistance.

The arrangement of this invention clearly minimizes one of the principal objections to Continuously loaded cables, that is, high cost due to increased size of the cable, increased duct space, shipping weight, etc., and is also particularly adapted to t-he most vmodern type ofphantom circuits. It is also believed to be more economical than coil loading spaced at sutliciently short intervals to give a cutoff frequency above the carrier range. Furthermore, the cutottl frequency obtained with the continuous loading of this invention is unusually high compared with thecutoff frequency obtained with lumped coil loading having the sameinductance per mile.

Inl carrier current loading systems, present practice is to place a loading coil in the line of 4.83 M. H. every 930 feet when, for example, the total capacity per section of the line is .01221111 f. Under these conditions the at` tenuation is low and uniform for all frequenciesup to the so-called cutoff frequency wlfhichk in the above case would be 41,500 cy` c es.

In accordance with the plan of this invention however, each 930 foot section would be composed of equal lengths of continuously loaded and non-loaded conductors. The ea pacity persection would then be only one half'that in the lumped loaded case or .0061 In. f.A This With the same amount of loading per Section, namely 4.83 m. h. per sectionl gives a ycuto frequency of 50,000 cycles. The total loop inductance is the same in both cases but the cutoi" frequency is someance with this invention, thus permitting carrier operation at even higher frequencies: than with standard loading of the same in ductance per section.

An obvious extension of the arrangement shown in the drawing is to apply continuous loading to only one-third or one-fourth of the quads in each section, so that the loaded quad of one section would be connected to a non-loaded quad in the next two or three sec tions, as the case may be. Another form this invention may take is to load all the quads in a plurality of sections of the cable and to connect them by one or more interposed sections of cable composed entirely of non-loaded quads.

Other modifications of the arrangement disclosed may also be made without departing in anywise from the spirit of this invention, as defined in the appended claims.

The invention claimed is:

1. A ransinission line comprising a pair of line conductors arranged' in alternately recurring continuously loaded and non-loaded sections, each loaded section comprising a pair of line conductors and means l'or continuously loading said conductors throughout the section, said loaded sections being substantiall),v uniformly spaced along said line.

2. A signaling cable, comprising a pluw rality of quads divided along their length into a plurality of arbitrary sections, each of the sections of said cable comprising a plurality of continuously loaded quads, and a plurality of non-loaded quads, each loaded quad in each section bein connected to a non-loaded quad in a su cient number of adjacent sections to distribute uniformly the loaded quads between the non-loaded quads for each resulting signaling path. j 3. A carrier frequency toll cable comprising a plurality of sections spliced together, each section comprising a plurality of quadded conductors, one-haltof said quads being continuously loaded, the remaining half of said quads being non-loaded, each loaded quad in each section being connected to a non-loaded quad in the two adjacentlsections.

4. A signaling system comprising a plurality of signaling conductors divided into a plurality of sections, certain of said sections comprising conductors continuously loaded by a wrapping of magnetic material,

plurality of said sections comprising nonloaded conductors, the loaded conductors being connected to non-loaded conductors in adjacent sections to uniformly space the loaded portions along each signaling path formed thereby.

5. A loaded line comprising alternately recurring continuously loaded and non-loaded sections, each loaded section comprising a line ,conductor and means for continuously loading said conductor throughout the seetion, said loaded sections being substantially uniformly spaced along said line.

G. A loaded signaling line comprising a plurality ot :non-loaded sections and a plie rality of continuously loaded sections, each of said loaded sections comprising a line conductor and means for continuously loading said conductor, the non-loaded sections being connected to the loaded sections to substantially uniformly space the loaded sections alo-ng the line.

7. A loaded signaling line comprising a plurality ol non-loaded sections and a plu rality of continuously loaded sections, each ol said loaded sections comprising a line con ductor and a layer of magnetic material surrounding said conductor, the non-loaded seetions being connected to the loaded sections to substantially uniformly space the loaded sections along the line.

8. A signaling system comprising a plurality of loaded conductors employing a plurality ot sections, certain of said sections comprising conductors continuously loaded by being surrounded by a layer of magnetic material, a plurality olf said sections com prising non-loaded conductors, the loaded Conductors being connected to the non-loaded conductors in adjacent sections to substantially uniformly space the loaded sections along each signaling path formed thereby.

9. A signaling system comprising a plurality of signaling conductors Which may be considered divided into a plurality of sections, a plurality of the conductors in each of said sections being non-loaded, means associated with a second plurality of conductors in each oit said sections whereby said second plurality oi conductors are continuously loaded, said sections being so connected that a loaded conductor in one section iS connected to a nonsloaded conductor in other sections to substantially uniformly space the loaded sections along each signaling path.

l0. In a transmission system a group of line conductor pairs divided into sections at the same points along their lengths, certain conductor pairs in the section between two given points of division being non-loaded and certain of the pairs in the same section being continuously loaded, similarly loaded conductor pairs and non-loaded pairs in the successive sections, the loaded conductor pairs of each section being connected to nonloaded conductor pairs of adjacent sections to form continuous transmission paths.

In Witness whereof, I hereunto subscribe my name this 2nd day of May, A. D. 1923. IVILLIAM FONDILLER. 

